Hub construction for variable pitch propellers or the like



July 4, 1950 Y R. E. B. SHARP 2,514,097 HUB CONSTRUCTION FOR VARIABLEPITCH PROPELLERS OR THE LIKE Filed Jan. 14, 1947 v 2 Sheets-Sheet 1Diaphragm unsfressed IN VEN TOR.

R. E B SHARP y 4, 1950 R. E. B. SHARP 2,514,097

HUB CONSTRUCTION FOR VARIABLE PITCH PROPELLERS OR THE LIKE Filed Jan.14, 1947 2 Shee ts-Sheet 2 I I I ll 36 20 F/G. j

--28 f 1 23 LgU INVENTOR. E. E. B. SHARP Patented July 4, 1950 HUBCONSTRUCTION FOR PITCH PROPELLERS on T E LIKE Robert E. B. Sharp, York,Pa.,'assignor to S. Morgan Smith Company, York, Pa., a corporation ofPennsylvania Application January 14, 1947, Serial No. 721,944

Claims.

This invention relates to rotors having adjustable blades and morespecifically to the construction of the hubs thereof.

An important object of the invention is the provision, in a constructionof this type, of an arrangement whereby the bearings in which theadjustable blades are mounted and the operating connections by whichadjustment of the blade position is obtained, can be fully andconstantly lubricated.

Another and more specific object of the invention is the provision of astructure of this character wherein a hub, having internal bearingsmounting a plurality of rotatability, adjustable blades projectingtherefrom, is provided with a sealing means between the rotating bladesand hub shell of such character that the hub structure is maintained asa sealed container without regard to the positional adjustment of thevblades.

A further and still more specific object of the invention is theprovision means for maintaining within a hub of this character apressure substantially equal to that to which the sealing means betweenthe hub and blades is externally subjected.

These and other objects are obtained by the construction showed in theaccompanying drawings, wherein, for the purpose of illustration, I haveshown my invention as applied to a ship propeller hub, and wherein:

Figure 1 is a fragmentary longitudinal section through a propeller hubconstruction in accordance with my invention,

Figure 2 is a fragmentary sectional view taken on line 2-2 of Figure 1.

Figure 3 is a section similar to that of Figure 1 showing the operatingshaft moved further into the hub, and

Figure 4 is a section on line i4 of Figure 1.

Referring more particularly to the drawings, the numeral Ill designatesa shaft having a flange II by means of which it is attached as at l2 tohub l3, said hub mounting radial blades 14, only one of which is hereinillustrated. The hub 13 comprises a shell [5, having an upper wall Itengaged by securing the elements l2, sockets H, for the reception of theshanks l8 of blades l4, and a rear end closure l9, more particularlydescribed hereinafter.

Shaft 16 is hollow and has directed therethrough means for rotatingblades Id. In the present instance, the rotating means comprises areciprocatory shaft 20, having bearing in the shell at 2| and havingsecured thereto a collar 22 including projecting arms 23 for connectionto stems I8. Stems l8 are mounted in spaced bearings 24 and 25,supported by shell l5, and an extended tubular portion of the upper wall[3 respectively, and in the present instance have secured thereto,intermediate bearings 24 and 25, collars 21 linked at 28 to arms 23,whereby reciprocation of shaft 2c will result in rotative oscillation ofthe stems l8 and consequently of blades M. It is to be understood thatthis-means of oscillation of the blades is purely illustrative'and maybe substituted for by any of the well-known means through whichadjustable blades of this character are manipue lated. i

In accordance'with my invention, the hubs of blades l4 and the shellsurrounding the hubs, are connected by'diaphragms 29, which may beconstructed of any suitable substance which is resistant to an internallubricant and the external fluid, and which is not only resilient butelastic to withstand distortion as hereinafter explained. ,Thisdiaphragm is sealed by clampingmeans 30 at .itsperiphery to shell l5 andby clamping means 31 at its inner diameter to the hub of blade [4. Sincethe blade I4 is rotatably adjustable; the diaphragm is of materialsufficiently elastic to withstand distortion between its normaloperating position A shown in Figure 2, and its maximum adjustmentpositions, in-

dicated at B and C respectively, the diaphragm 29 being undistorted atthe medial or operating position A for obvious'reasons.

The hub shell, and more specifically the end cap of closure I9 ,theneof,includes an expansible chamber 32, internal wall of which is in the formof a flexible diaphragm 33. The interior of chamber 32 is connectedthrough a suitable conduit 34 with, the exterior of the hub at a pointessentially in a'plane including the axes of blade shanks it. It isrecognized that in the case of rotors having adjustable blades such asships propellers, hydraulic turbine runners, pump impellers, or wheresuch a rotor operates in any fluid, the external pressure at theup-stream end of the hub exceeds that of the rear or downstream end. Byconnecting the expansible chamber 32 to the exterior of the hub at apoint where the average external pressure exists, the difference inpressure between the exterior and. interior of the hub is minimized,with the result that diaphragms 29 are not subjective to materialpressure differences therein at the interior and exterior surfaces, withthe increasing reduction in wear which would occur where these press 3sure differences cause displacement of the diaphragm to an extentcausing contact thereof with one or another of the relative movablesurfaces between which they are disposed.

To seal the chamber within which the hub stmes are mounted, I provide aseal between the upper end wall I6 of hub l3 and the reciprocatory shaft20. At the present this seal comprises a collar 35 which may be integralwith or secured to shaft 20 and a diaphragm 36 sealed to this collar andto the upper end wall 1'6 of shell 15.

It is furthermore pointed out that in a construction of this sort wherethe hub is in a form of a sealed chamber and a reciprocating control forpitch variation is utilized, the capacity of this chamber will vary inaccordance with the position of operating shaft 2! Expansible chamber 32serves not only as a means for equalizing internal and externalpressures as outlined above, but likewise as a means for compensatingfor this variation of internal capacity and to eliminate strains whichwould otherwise be placed upondiaphragms 29 and 35. All of thediaphragms 29, 33 and 3B are provided with circum. ferentially extendingcorrugations or are otherwise designed to permit the desired deflection.In the case of diaphragms 33 and 36, thepurpose of such corrugationswill be readily understood, and in the case of diaphragms 29, as pointedout, these circumferential corrugations give to diaphragms 29 increasedradial length which assists in reducing fatigue resulting fromcircumferential distortion.

Since the construction illustrated in the foregoing is purely an exampleof one method of producing my invention and the arrangement illustratedis obviously capable of considerable modification, I do not wish to beunderstood as limiting myself thereto, except as hereinafter claimed.'

I claim:

1. In an adjustably bladed rotor adapted to operate in a fluid medium, ahollow hub, blades having shanks mounted for oscillation in bearings insaid hub, elastic diaphragms surroundingsaidshanks, said diaphragmsbeing sealedat their peripheries to said hub and blade shanks,

said hub, a fluid lubricant in said hub, said hub including aninteriorly disposed expansible'chamher the interior of which is incommunication with the exterior of the hub in a zone of averagepressure.

2. In an adjustably bladed rotor adapted to operate in a fluid medium, ahollo hub, a rotor shaft mounting said hub, blade having shanks mountedfor oscillation in bearings in said hub, elastic diaphragms surroundingsaid shanks, said diaphragms being sealed at their peripheries to saidhub and blade shanks, positioning means for said blades including asolid shaft extending through said rotor shaft and into said hub, meanseffecting a fluidtight seal between said positioning shaft and hub,operating connections between said positioning mean and blade shankswithin said hub, a fluid lubricant in said hub and said ltioning meansfor said blades including a solid shaft extending into said hub, meanseffecting a 'fiuidtight seal between said positioning shaft and hub,operating connections between said po- 'sitioning means and blade shanksWithin said hub, a fluid lubricant in said hub, said hub in- V eludingan interiorly disposed expansible chamher the interior of which is incommunication with the exterior of the hub in a zone of average '1.pressure, the first named diaphragms being provided withciroumferentially extending corrugations.

4. In an adjustably bladed rotor adapted to opcrate in a fluid'mediu'm,a hollow hub, a rotor shaft mounting said hub, blades having shanksmounted for oscillation in hearings in said hub, elastic diaphragmssurrounding said shanks, said diaphragms being sealed at theirperipheries to said hub and blade shanks, positioning means for saidblades including a single shaft extending through said rotor shaft andinto said hub, means efiecting a fluidtight seal between saidpositioning shaft and hub, operating connection between said positioningmeans and blade shanks within said'hub, a fluid lubricant in said huband said hub including an interiorly disposed expansible chambertheinterior of which is in communication with the exterior'of the hub'ina zone of average pressure, the first named diaphragm being providedwith circumferentially extending corrugations.

5, In an adjustably bladed rotor adapted to operate in a fluid medium, ahollow hub, a hollow shaft mounting said hub, blades having shanksmounted for oscillation in said hub, a reciprocating shaft extendingthrough said hollow shaft and connected to the blade shank to oscillatethe same, sealing means between said blade shanks and hub and betweensaid'shaft and hub whereby to form the hub asa sealed lubricantreceiving chamber, and an expansiblechamber having a movable wall withinthe hub and having its interior in communication with the exterior ofthe hub.

ROBERT E. B. SHARP.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 734,468 McCollum July 21, 19031,510,086 Englesson Sept. 30, 1924 2,421,841 Lowy June 10, 1947 FOREIGNPATENTS Number Country Date 28,257 Denmark Aug. 15,1921

